U.S. patent number 4,430,477 [Application Number 06/498,504] was granted by the patent office on 1984-02-07 for polypropylene composition.
This patent grant is currently assigned to Chisso Corporation. Invention is credited to Kohichi Kunimune.
United States Patent |
4,430,477 |
Kunimune |
February 7, 1984 |
Polypropylene composition
Abstract
A propylene composition having a notably improved high-impact
strength and elongation at break, with a relatively slight
reduction in rigidity is provided, which composition is a
high-impact polypropylene composition comprising 60 to 95 parts by
weight of polypropylene and 40 to 5 parts by weight of a
chlorinated polyolefin having styrene graft-polymerized
thereon.
Inventors: |
Kunimune; Kohichi (Ichiharashi,
JP) |
Assignee: |
Chisso Corporation (Osaka,
JP)
|
Family
ID: |
14135440 |
Appl.
No.: |
06/498,504 |
Filed: |
May 26, 1983 |
Foreign Application Priority Data
|
|
|
|
|
Jun 3, 1982 [JP] |
|
|
57-95359 |
|
Current U.S.
Class: |
525/70; 525/193;
525/249; 525/324; 525/75; 525/76 |
Current CPC
Class: |
C08L
23/10 (20130101); C08L 23/286 (20130101); C08L
51/06 (20130101); C08F 255/023 (20130101); C08L
23/10 (20130101); C08L 23/10 (20130101); C08L
23/10 (20130101); C08L 23/286 (20130101); C08L
51/06 (20130101); C08L 2666/24 (20130101); C08L
2666/02 (20130101); C08L 2666/04 (20130101) |
Current International
Class: |
C08L
23/00 (20060101); C08L 23/10 (20060101); C08L
51/06 (20060101); C08L 51/00 (20060101); C08L
051/06 (); C08L 023/12 (); C08L 023/28 () |
Field of
Search: |
;525/70,324 |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
3496251 |
February 1970 |
Takahashi et al. |
3558745 |
January 1971 |
Ogawa et al. |
3565974 |
February 1971 |
Ohnuma et al. |
3673279 |
June 1972 |
Takahashi et al. |
3819763 |
June 1974 |
Akane et al. |
4112013 |
September 1978 |
Briggs et al. |
|
Primary Examiner: Seccuro; Carman J.
Attorney, Agent or Firm: Philpitt; Fred
Claims
What is claimed is:
1. A high-impact polypropylene composition comprising 60 to 95
parts by weight of polypropylene and 40 to 5 parts by weight of a
chlorinated polyolefin having styrene graft-polymerized thereon
(hereinafter abbreviated to Cl.PO-g-St).
2. A polypropylene composition according to claim 1 wherein the
chlorine content of said chlorinated polyolefin is 5 to 50% by
weight and the styrene content of said Cl.PO-g-St is 5 to 40% by
weight.
3. A polypropylene composition according to claim 1 wherein said
chlorinated polyolefin is a chlorinated polyethylene or a
chlorinated EPM.
4. A polypropylene composition according to claim 2 wherein said
chlorinated polyolefin is a chlorinated polyethylene or a
chlorinated EPM.
5. A polypropylene composition according to claim 1 wherein said
Cl.PO-g-St is obtained by graft-polymerizing styrene on a
chlorinated polyolefin in the presence of a catalyst having as its
main component, an organoaluminum compound expressed by the general
formula
wherein R represents the same or different alkyl, aryl or aralkyl
groups; X represents a halogen atom; and n represents a number of
1, 1.5, 2 or 3.
6. A polypropylene composition according to claim 2 wherein said
Cl.PO-g-St is obtained by graft-polymerizing styrene on a
chlorinated polyolefin in the presence of a catalyst having as its
main component, an organoaluminum compound expressed by the general
formula
wherein R represents the same or different alkyl, aryl or aralkyl
groups; X represents a halogen atom; and n represents a number of
1, 1.5, 2 or 3.
7. A polypropylene composition according to claim 3 wherein said
Cl.PO-g-St is obtained by graft-polymerizing styrene on a
chlorinated polyolefin in the presence of a catalyst having as its
main component, an organoaluminum compound expressed by the general
formula
wherein R represents the same or different alkyl, aryl or aralkyl
groups; X represents a halogen atom; and n represents a number of
1, 1.5, 2 or 3.
8. A polypropylene composition according to claim 4 wherein said
Cl.PO-g-St is obtained by graft-polymerizing styrene on a
chlorinated polyolefin in the presence of a catalyst having as its
main component, an organoaluminum compound expressed by the general
formula
wherein R represents the same or different alkyl, aryl or aralkyl
groups; X represents a halogen atom, and n represents a number of
1, 1.5, 2 or 3.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a polypropylene composition. More
particularly it relates to a high-impact polypropylene composition
comprising polypropylene and a chlorinated polyolefin having
styrene graft-polymerized thereon (hereinafter abbreviated to
Cl.PO-g-St).
2. Description of the Prior Art
Polypropylene is superior in chemical and physical properties and
has been used in a large amount as a general-purpose resin, but
from a viewpoint of practical physical properties, it has a
drawback of being inferior in high-impact strength. In order to
overcome this drawback, a great deal of effort and a number of
proposals have so far been made, and any of them are roughly
classified into a process of blending a rubbery material to
polypropylene and a copolymerization process wherein ethylene,
butene-1 or the like is used as a copolymerization component in
propylene polymerization. The blending process has had drawbacks
that if the amount of a rubbery material added is increased in
order to increase the high-impact strength of polypropylene, the
rigidity and hardness of polypropylene as its merits are notably
reduced and further its compatability becomes inferior to reduce
its transparency, luster, surface smoothness, etc. On the other
hand, the copolymerization process also has had drawbacks that as
the amount of copolymerized component is increased, mechanical
properties of polypropylene such as rigidity, hardness, etc. become
inferior, and also thermal properties such as melting point,
softening point, etc. become notably inferior; hence it has been
difficult to make these properties consistent with high-impact
properties.
The present inventor have made strenuous efforts in order to solve
the above-mentioned problems relative to improvement in the
high-impact properties of polypropylene, and as a result, have
found that when a specified polymer is blended to polypropylene, it
is possible to improve the high-impact properties while the
reduction in rigidity and hardness is kept minimum.
SUMMARY OF THE INVENTION
The object of the invention is to provide a propylene composition
having the reduction in rigidity well balanced with the improvement
in high-impact properties.
The present invention resides in:
(1) a high-impact polypropylene composition comprising 60 to 95
parts by weight of polypropylene and 40 to 5 parts by weight of a
chlorinated polyolefin having styrene graft-polymerized thereon
(hereinafter abbreviated to Cl.PO-g-St);
(2) a polypropylene composition according to the above item (1)
wherein the chlorine content of the chlorinated polyolefin is 5 to
50% by weight and the styrene content of the Cl.PO-g-St is 5 to 40%
by weight;
(3) a polypropylene composition according to the above item (1) or
(2) wherein the chlorinated polyolefin is a chlorinated
polyethylene or a chlorinated EPM; and
(4) a polypropylene composition according to the above item (1),
(2) or (3) wherein the Cl.PO-g-St is obtained by graft-polymerizing
styrene on a chlorinated polyolefin in the presence of a catalyst
having as its main component, an organoaluminum compound expressed
by the general formula
wherein R represents the same or different alkyl, aryl or aralkyl
groups; X represents a halogen atom; and n represents a number of
1, 1.5, 2 or 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The chlorinated polyolefin refers to chlorinated products of
polymers or copolymers of lower olefins such as ethylene,
propylene, butene, etc., and concrete examples thereof are
chlorinated polyethylenes obtained by chlorinating low density
polyethylene, medium density polyethylene, high density
polyethylene, low pressure low density polyethylene or the like,
chlorinated polypropylenes obtained by chlorinating crystalline
isotactic polypropylene or non-crystalline atactic polypropylene,
chlorinated polybutenes obtained by chlorinating crystalline
polybutene prepared by polymerizing butene-1 in the presence of the
so-called Ziegler system catalyst or obtained by polymerizing
isobutene in the presence of a cationic polymerization catalyst,
and further, chlorinated products of EPM or EPDM, etc.
As for the chlorinated polyolefins, those having a chlorine content
of 5 to 50% by weight, preferably 15 to 40% by weight are used. If
the chlorine content is less than 5% by weight, the effectiveness
of improvement in physical properties of polypropylene is
insufficient, while if the content exceeds 50% by weight, the
compatibility of the chlorinated polyolefin with polypropylene is
reduced to make the physical properties of the resulting
composition inferior. Thus the contents outside the above range are
undesirable.
As for the process for graft-polymerizing styrene on the
chlorinated polyolefin, it is possible to employ a known method
such as solution polymerization or suspension polymerization or the
like in the presence of a free-radical initiator such as benzoyl
peroxide or azobisbutyronitrile, as catalyst. Graft copolymers
obtained according to these methods can be used as a component of
the composition of the present invention. Further, polymers
obtained by graft-polymerization styrene on a chlorinated
polyolefin according to a polymerization method such as solution
polymerization or suspension polymerization or the like in the
presence of an organoaluminum compound as catalyst, expressed by
the general formula AlR.sub.n X.sub.3-n wherein R represents the
same or different kinds of alkyl, aryl or aralkyl groups; X
represents a halogen atom; and n represents a number of 1, 1.5, 2
or 3, have a superior heat stability at the time of
melt-processing; hence they are suitably used as a component of the
composition of the present invention.
As for the thus obtained graft copolymers, those having a styrene
content of 5 to 40% by weight, preferably, 10 to 25% by weight are
used for the present invention. If the styrene content is less than
5% by weight, the effectiveness of improvement in physical
properties of polypropylene is poor, while if it exceeds 40% by
weight, its compatibility with polypropylene is reduced. Thus, the
contents outside the range are undesirable.
Polypropylene as a main component of the composition of the present
invention refers to crystalline polypropylene obtained by
polymerizing propylene in the presence of the so-called
Ziegler-Natta type catalyst, and it also refers to not only
homopolymer of propylene but also copolymers of propylene as a main
component with ethylene, butene-1, 4-methyl-pentene or the like.
The polypropylene has no particular limitation to its melt flow
rate (MFR), but if a notable effectiveness of improvement in
processing properties and physical properties are taken into
consideration, its MFR is suitably in the range of 0.5 to 30,
preferably 1 to 15.
The proportions of polypropylene and Cl.PO-g-St to be blended
thereto in the composition of the present invention is in the range
of 60 to 95 parts by weight of polypropylene and 40 to 5 parts by
weight of Cl.PO-g-St. If the proportion of Cl.PO-g-St exceeds 40
parts by weight, its compatibility with polypropylene is reduced to
make the physical properties of the resulting composition inferior,
while if it is less than 5 parts by weight, the effectiveness of
improvement in physical properties of polypropylene is
insufficient; hence the proportions outside the above range are
undesirable.
Blending of polypropylene to Cl.PO-g-St can be effected by
melt-kneading them at a resin temperature of 170.degree. to
220.degree. C. using a known apparatus such as extruder, heated
rolls, Banbury mixer or the like. If the resin temperature is lower
than 170.degree. C., fusion of the resins is insufficient, while if
it exceeds 220.degree. C., thermal decomposition of Cl.PO-g-St is
notable; hence the temperatures outside the range are undesirable.
In this blending it is possible to add agents to be usually
incorporated into polypropylene such as stabilizer, coloring agent,
filler, etc. in the range where the object of the present invention
is not damaged.
The propylene composition of the present invention can be molded
into various molded products, sheets, films or the like according
to usual molding process such as injection molding process, blow
molding process, extrusion molding process. The thus obtained
molded products have a much improved high-impact strength without
notable reduction in the rigidity and hardness intrinsic of
polypropylene.
Further, the composition of the present invention contains
chlorine, and when an inorganic filler such as antimony oxide,
aluminum hydroxide or the like is blended to the composition, or
not blended thereto, the composition has an improved flame
retardancy and hot melt adhesive properties to inorganic stocks
such as metal, glass, etc.
The present invention will be concretely described below by way of
Examples.
The methods for measuring values of physical properties shown in
Examples are as follows:
Preparation of test pieces: Molded at a resin temperature of
200.degree. C., using Min-Max molding machine (manufactured by
Cust. Sci. Inst. Co.).
Tensile test: Measured at 25.degree. C., at a tensile rate of 23.0
mm/min., using Min-Max tensile tester manufactured by Cust. Sci.
Inst. Co.
Tensile impact test: Measured using Min-Max impact tester
manufactured by Cust. Sci. Inst. Co.
EXAMPLES 1.about.4 AND COMPARATIVE EXAMPLES 1.about.3
Powder of a chlorinated polyethylene having chlorine content of 35%
by weight (150 g), prepared by chlorinating a low density
polyethylene having a melt index (MI) of 20 was taken into a 2 l
capacity glass flask purged with nitrogen gas in advance, and
successively n-hexane (500 ml) and diethyl aluminum chloride (15
mmols) were added. Then, while the temperature inside the flask was
kept at 20.degree. C., styrene (100 ml) was gradually dropwise
added through a dropping funnel with stirring over 30 minutes for
reaction, followed by further continuing the reaction with stirring
for one hour. After lapse of the reaction time, methanol (50 ml)
was dropwise added to deactivate the catalyst, followed by
filtering off and washing the resulting reaction product with a
large amount of methanol and drying in vacuo at 50.degree. C. over
night to obtain a graftmer (Cl.PE-g.St) having a styrene content of
16% by weight (175 g).
This graftmer in amounts indicated in Table mentioned below was
blended to two kinds of crystalline polypropylene one of which had
a melt flow rate (MFR) of 4 and the other of which had a melt flow
rate of 10, respectively. To the resulting composition was added
BHT (3,5-di-t-butyl-4-hydroxytoluene) (0.02 phr), followed by
kneading and granulation at a resin temperature of 200.degree. C.
by means of an extruder. All of the resulting pellets were white
and had a smooth and lustrous surface. The blending ratios and the
results of the test of physical properties are shown in the
Table.
For comparison, the above-mentioned two kinds of polypropylene,
each alone, and a blend of 70% by weight of the above polypropylene
having a MFR of 4.0 to 30% by weight of an EPM were granulated as
in Examples. The values of physical properties and the results are
also shown in the Table. In addition, the EPM had a MI of 0.6, an
ethylene content of 60% by weight and a propylene content of 40% by
weight.
EXAMPLES 5 AND 6
Using the same apparatus and procedure as in Example 1, a
chlorinated polyethylene having a chlorine content of 15% by weight
(100 g), prepared by chlorinating a high density polyethylene
having a MI of 0.8, n-pentane (500 ml) and diethylaluminum chloride
(18 mmols) were fed, and while the temperature inside the flask was
kept at 10.degree. C., styrene (150 ml) was dropwise added with
stirring over 30 minutes for reaction, followed by further
continuing the reaction with stirring for one hour. After lapse of
the reaction time, termination of the reaction, filtering off,
washing and drying were carried out as in Example 1 to obtain a
graftmer (Cl.PE-g.St) having a styrene content of 23% by weight
(123 g).
Using the same apparatus and procedure as in Example 1, this
graftmer was blended to a polypropylene having a MFR of 4.0 in
proportions indicated in the Table, followed by granulation. All of
the resulting pellets were white and had a smooth and lustrous
surface. The values of physical properties of these products are
shown in the Table.
COMPARATIVE EXAMPLES 4 AND 5
The chlorinated polyethylene used in Example 1 and that used in
Example 5 were respectively blended in a blending proportion of 30%
by weight, to 70% by weight of a polypropylene having a MFR of 4.0,
followed by adding BHT (0.02 phr) and kneading and granulating at a
resin temperature of 200.degree. C., by means of an extruder. All
of the resulting pellets were colored to yellow and had a roughened
and non-lustrous surface.
EXAMPLES 7 AND 8 AND COMPARATIVE EXAMPLES 6 AND 7
Into the same apparatus as in Example 1, purged with nitrogen gas,
were fed a chlorinated EPM having a chlorine content of 15% by
weight (100 g), prepared by chlorinating an EPM having an ethylene
content of 60% by weight, a propylene content of 40% by weight and
a MI of 0.6, and toluene (800 ml), and these were agitated to
dissolve the chlorinated EPM, followed by adding diethylaluminum
(15 mmols). Then, while the temperature inside the flask was kept
at -10.degree. C., styrene was dropwise added with stirring over
one hour for reaction, and the reaction was further continued with
stirring for 2 hours. After lapse of the reaction time, methanol
(50 ml) was added to deactivate the catalyst, and the resulting
reaction liquid was fed in a large amount of methanol to
precipitate polymer, followed by filtering off, washing and drying
as in Example 1 to obtain a graftmer (Cl.EPM-g-St) having a styrene
content of 28% by weight (125 g).
Using the same apparatus and procedure as in Example 1, this
graftmer was blended to a crystalline polypropylene having a MFR of
15 in proportions indicated in the Table, followed by granulation.
All of the resulting pellets were white and had a smooth and
lustrous surface. The blending proportions and the results of the
test of physical properties are shown in the Table.
For comparison, the above polypropylene alone and a blend of 70% by
weight of this polypropylene to 30% by weight of EPM were
granulated as in Example 1. The values of physical properties of
these products are also shown in the Table.
__________________________________________________________________________
Blending Physical properties Polypropylene Graftmer Elongation
Tensile Tensile impact Blending Blending at break modulus strength
MFR ratio ratio % Kg/cm Kg .multidot. cm/cm.sup.2
__________________________________________________________________________
Example 1 4 90 10*.sup.1 >220 10,900 57 Example 2 4 70 30*.sup.1
>220 9,200 91 Example 3 10 90 10*.sup.1 >220 10,900 52
Example 4 10 70 30*.sup.1 >220 9,400 81 Compar. 4 100 -- 65
12,000 35 ex. 1 Compar. 10 100 -- 60 12,300 33 ex. 2 Compar. 4 70
30*.sup.2 >220 7,400 70 ex. 3 Example 5 4 85 15*.sup.3 >220
10,500 54 Example 6 4 65 35*.sup.3 >220 9,300 85 Example 7 15 90
10*.sup.4 >220 10,800 55 Example 8 15 70 30*.sup.4 >220 9,000
76 Compar. 15 100 -- 60 12,400 28 ex. 6 Compar. 15 70 30*.sup.2
>220 7,400 68 ex. 7
__________________________________________________________________________
*.sup.1 Cl.PE gSt: St content 16% *.sup.2 EPM: MI = 0.6,
C.sub.2.sup..dbd. = 60%, C.sub.3.sup..dbd. = 40 *.sup.3 Cl.PE gSt:
St content 23% *.sup.4 Cl.EPM gSt: St content 28%
As apparent from the above results, if a rubbery material such as
EPM is blended to polypropylene, high-impact properties of the
latter are improved, but its rigidity is notably reduced, and if a
chlorinated polyethylene is blended to polypropylene, the resulting
blend causes heat deterioration under processing conditions of
polypropylene; hence desirable results cannot be obtained. Whereas,
in the case of the composition of the present invention, it is
observed that the high-impact strength and elongation at break of
polypropylene are notably improved with a relatively slight
reduction in rigidity.
* * * * *